All-terrain vehicle

ABSTRACT

Disclosed herein is an all-terrain vehicle including a body, a power generating and transmission group, and a track suspension group, each of which can be separately initially fabricated and subsequently assembled. After assembly of the power generating and transmission group and the track suspension group to the body, a motor hood, drive sprocket, and tracks may additionally be assembled to complete the vehicle. Also disclosed herein is a track suspension system affording both transverse and lateral resiliently flexible support to an endless track and a releasably locked and pivotally mounted rear bogie wheel assembly which, when pivoted from its normal operating position, affords assembly of or removal of the endless track relative to the sprocket and bogie wheels. Also disclosed herein is a track sprocket affording maximum open area for the escape of mud, snow, ice and the like. Also disclosed herein is a hydrostatic transmission including a control having a reverse lock-out preventing accidental movement of the control into position effecting reverse operation. Still further, there is disclosed herein a hydraulic oil circulating system which utilizes the gear box as a sump for the circulating system and which is in heat exchanging relation with an air circulating system.

United States Patent 1 1 3,776,325 Jespersen [451 Dec. 4,1973

[ 4] ALL-TERRAIN VEHICLE [75] Inventor; Herbert A.Jespersen, Lincoln,[57] ABSTRACT Nebr.

[7 3] Assignee: Outboard Marine Corporation,

Waukegan, Ill.

[22] Filed: Nov. 27, 1970 [21] Appl. No.1 93,471

Related U.s. Application Data [62] Division of Ser. No. 857,494, Sept.12, 1969,

Primary Examinerl(enneth H, Betts Assistant Examiner-Leslie J A PapemerAttorney-Wheeler, Wheeler, House and Clemency Disclosed herein is anall-terrain vehicle including a body, a power generating andtransmission group, and a track suspension group, each of which can beseparately initially fabricated and subsequently assembled. Afterassembly of the power generating and transmission group and the tracksuspension group to the body, a motor hood, dr ive sprocket, and tracksmay additionally be assembled to complete the vehicle.

Also disclosed herein is a track suspension system affording bothtransverse and lateral resiliently flexible support to an endless trackand a releasably locked and pivotally mounted rear bogie wheel assemblywhich, when pivoted from its. normal operating position, affordsassembly of or removal of the endless track relative to the sprocket andbogie wheels.

Also disclosed herein is a track. sprocket afiording maximum open areafor the escape of mud, snow, ice and the like.

7 Claims, 18 Drawing Figures 1111]! Hill PATENTEU HEB 41975 SHEET 2 0F(3 ill Pmmrmm 4191s 3.776325 SHEET ESP 6 PATENTEDDEE 4191s 3,776,325

' sum 5 OF 6 ALL-TERRAIN VEHICLE RELATED CASE This application is adivision of my co-pending application Ser. No. 857,494, filedSept. 12,1969, abandoned in favor of continuing application Ser. No. 175,376, nowUS. Pat. No. 3,688,858.

BACKGROUND OF THE INVENTION The invention relates to so-calledall-terrain vehicles which have a high capability for travel overdifficult and rpugh ground contours, conditions and textures. Theinvention also relates to track vehicles and especially to vehiclesadapted to travel over snow and mud. The invention further relates tomodular construction of such vehicles.

The invention further relates to sprocket constructions and to tracksuspensions. In connection with sprocket constructions, reference ismade to US. application Ser. No. 685,214, now US. Pat. No. 3,472,563.

The invention further relates to speed and steering controls and, inthis connection, reference is made to US. Pat. No. 644,853 and No.3,323,607.

The invention further relates to power generating and transmissionsystems and to air and oil circulating systems for hydraulically driventrack or other vehicles and to cooling arrangements for such systems.

SUMMARY OF THE INVENTION The invention provides a superior all-terrainvehicle capable of reliable performance over a wide range of groundconditions. One of the features of the invention resides in the modulararrangement or construction whereby major components of the vehicle canbe separately fabricated and subsequently assembled as a whole.

Morespecifically, the main components of the disclosed all'terrainvehicle include a body, a power generating and transmission group and atrack suspension group, each of which can be separately fabricated forfuture independent assembly with the body, thereby materially reducingthe complexity of assembling andfabricating and facilitating ease ofassembly and ready replacement in the case of need for repair or thelike.

Another of the features of the modular concept involves the use ofconventional hydraulic or hydrostatic transmission units which can bereadily connected to or removed from a gear box to provide superiortransmission operation and to afford ease of assembly and replacement.

Another of the features of the invention resides in the control systemfor the power generating and transmission group which includes a pair ofhydrostatic transmission units powered by a single internal combustionengine. The control system includes a T-bar stick controlling operationof the hydraulic transmission units to provide conditions of neutral,forward and reverse drive, as well as steering, together with a reverselockoutarrangement to prevent accidental operation in reverse.

Still another feature of the invention resides in the hydrauliccirculation system which utilizes the beforementioned gear box as thesump or reservoir for oil discharged from the hydrostatic units, therebyeconomically providing for lubrication of the various components withinthe gear box.

Still another aspect of the invention resides in the dual flow aircirculation system for cooling the oil circulation system and forsupplying combustion air to the engine, as well as for cooling of theengine.

Still another feature of the invention resides in the track suspensiongroup whereby both lateral and longitudinal resilient support isprovided for an endless belt or track. In this regard, the tracksuspension assembly, at each side of the vehicle body, includes aplurality of paired inner and outer bogie wheels which are located ingenerally adjacent transverse relation to each other and which aresupported for vertical movement independently of each other, whereby toafford resilient transverse flexible support for the endless belts.

In addition to the foregoing, each track assembly in cludes a rear bogiewheel assembly which is pivotally mounted to the supporting frame so asto afford displacement of the rear bogie wheels to a positionconveniently affording placement of the endless track about the drivesprocket and around the bogie wheel assemblies. Upon such assembly, therear bogie wheel assembly is swung back into its normal operatingposition and releasably locked in place to prevent loss of the endlesstrack from the suspension assembly.

Another of the aspects of the rear bogie wheel construction is thearrangement for maintaining track tension, notwithstanding any stretchor elongation which may occur to the track.

Still another feature of the rear bogie wheel assembly is thearrangement of an elastomeric mount to afford limited resilient movementof the rear bogie wheels from their normal operating position.

Still another feature of the invention is the drive sprocketconstruction which is arranged to afford a maximum opportunity forescape of ice, snow, mud, or

' the like, which otherwise could have a tendency to build up on thesprocket.

Still another feature of the invention resides in the generalarrangement of the various bogie wheels to the frame of the tracksuspension group and the arrangement for connection of the tracksuspension group to the body.

Still another feature of the invention resides in the relationshipbetween the bogie'wheel sprocket diameter and the lugs and the inside ofthe endless track. More specifically in this regard, the lugs and thediscs are dimensioned such that, at least two teeth are always engagedwithin each bogie wheel during movement of the track, thereby reliablyassuring retention of the track in proper aligned relation to theassociated track suspension system. h

In general, the principal object of the invention is to provide asuperior all-terrain vehicle which is economical to manufacture andassemble, which can be readily repaired, and which is entirely reliablein operation Other objects and advantages of the invention will becomeknown by reference to the following description and accompanyingdrawings in which:

DRAWINGS FIG. 1 is a perspective view of a track vehicle embodyingvarious of the features of the invention.

FIG. 2 is a sectional view taken transversely of the forward portion ofthe vehicle shown in FIG. 1.

FIG. 3 is an exploded elevational view, partially broken away insection, of the power generating and transmission group, the body, andthe track suspension group of the vehicle shown in FIGJI.

FIG. 4 is an enlarged and partially broken away view of a portion of thepower generating and transmission group and of the drive sprocketemployed in the vehicle shown in FIG. 1.

FIG. 5 is an end view of the sprocket shown in FIG. 4.

FIG. 6 is a schematic view, partially in section, of the oil circulatingsystem included in the power generating and transmission group of thevehicle shown in FIG. 1.

FIG. 7 is a front elevational view, partially in section, of a portionof the control for the power generating and transmission group of thevehicle shown in FIG. 1.

FIG. 8 is a side elevational view of the control shown in FIG. 7 withthe components being shown in their neutral drive condition.

FIG. 9 is a view similar to FIG. 8 with the components being shown intheir reverse drive condition.

FIG. 10 is a fragmentary view, partially in section, illustrating theconnection of the track suspension group to the body.

FIG. 11 is a sectional view taken along line 11ll of FIG. 10.

FIG. 12 is a front elevational view, partially in section, of the frontbogie wheel assemblies incorporated in the track suspension group of thevehicle shown in FIG. 1.

FIG. 13 is a sectional view taken along line l313 of FIG. 12.

FIG. 14 is a sectional view taken along line 1414 of FIG. 13.

FIG. 15 is a plan view, partially in section, of the rear bogie wheelassembly of the track suspension group.

FIG. 16 is an end elevational view, partially in sec tion, of the rearbogie wheel assembly shown in FIG. 15.

FIG. 17 is a sectional view taken along line 17-l7 of FIG. 15.

FIG. 18 is a fragmentary perspective view of a portion of the trackemployed on the vehicle shown in FIG. 1.

GENERAL DESCRIPTION Shown in the drawings and especially in FIG. 1, isan all-terrain vehicle 11 built in accordance with the invention. Thevehicle is desirably constructed by assembling three main assemblies ormodules (See FIG. 3), namely, a body 13, a power generating andtransmission group 15, and a track suspension group 17 which includes,on each side of the vehicle, a track suspension system 21. In additionto the foregoing, full construction of the vehicle is generallycompleted by assembling a motor hood 23 over the power group and byconnecting a pair of sprockets 25 to the power group and by training anendless longitudinal and transversely flexible track 27 around thesprocket 25 and track suspension system 21 at each side of the vehicle11.

THE BODY The vehicle body 13 is preferably molded of fiberglass,although other constructions and materials can be employed, to providean upwardly open hollow interior which receives the power group 15 andwhich supports the motor hood 23 and a seat 31 (See FIG. 1), as well asother components not specifically referred to.

More specifically, the body includes, see FIG. 2, a center section 35having a bottom wall 37 and front and rear walls 39 and 41 respectivelyextending upwardly from the bottom wall 37. Extending from. the bottomwall 37 and from the front and rear walls 39 and 41 are opposing sidewalls 43 which, together with the bottom, front and rear walls,generally complete the center section 35.

Located transversely on the undersurface of the bottom wall 37 (See FIG.3) are a plurality of spaced parallel downwardly open channels 45 whichare formed in the otherwise generally continuous bottom wall surface. Asexplained in greater detail hereinafter, the channels 45 cooperate withthe track suspension group 17 to permit modular assembly while, at thesame time, affording maximum vertical clearance under the bottom wall 37and between the tracks 27, consistent with maintaining watertightintegrity of the body and maximum depth to afford sufficient space inthe center section 35 for the power group 15 and for the users legs.While various arrangements are possible, the disclosed constructionincludes forward, rearward, and intermediate channels.

Extending oppositely and laterally outwardly from the upper portion ofeach of the side walls 43 are (See FIG. 2) deck or extension walls 49which, along their outer peripheries, have upwardly extending flanges 51which merge with the front and rear walls 39 and 41.

Except for a pair of opposed and aligned openings 55 (See FIG. 2), whichwill shortly be described, and except as may otherwise be indicatedherein, the resulting construction is generally continuous and thereforgenerally watertight to adjacent the top edges of the front wall, rearwall and flanges.

Each of the opposed and aligned openings 55 is provided, as will beexplained in greater detail hereinafter, to facilitate assembly of thepower group 15 with the body 13, and includes a part 57 in theassociated side wall 43 and a part 59 in the adjacent associated deckwall 49. More particularly, the side wall part 57 of each opening 55extends from upwardly of the bottom of the associated side wall 43 tothe adjacent deck wall 49 and the deck wall part 59 extends inwardly ofthe outer periphery thereof to the side wall part 57 to provide, withthe adjacent side wall part, a continuous opening.

The body 13 can be provided with one or more vertical openings, as maybe desired, to afford passage of items such as an exhaust pipe which canextend through the bottomof the vehicle and then rearwardly. Suchvertical openings can be defined by a cylinder wall having a heightabove the bottom wall 37 approximately the same as the height of the topedges of the front wall, rear wall, and flanges, whereby such verticalopenings do not detract from the watertight integrity of the body.

THE POWER GENERATING AND TRANSMISSION GROUP The power. generating andtransmission group 15 principally includes (as seen best in FIG. 3) aframe 71 which is connectable to the body 13, an engine 73, and

75, and a radiator 79 which is supported above the gear box 75 at thefront of the power group 15, and a hydraulic transmission control system81 which regulates the hydrostatic transmission units to afford speedand steering operation. In addition, the power group includes a separatecontrol for engine speed.

Extending from the gear box 75 is an axle means which, in the disclosedconstruction,.is in the form of two generally axially aligned shafts 83.Associated with each of the axle shafts 83 to span the previouslydisclosed body openings 55 are respective L-shaped closures 85 whichhave contours conforming generally to the margins of the inner surfaceof the body 13 around the openings 55 and which include deck and sidewall portions or legs 85A and 8513.

More particularly, the frame 71 can be suitably constructed in anydesired way and is arranged to be suitably connected, as by bolts or thelike, to the body. More specifically, as shown best in the upper part ofFIG. 3, the frame 71 includes a central generally horizontally extendingforwardly open U-shaped member 89 which, at its forward ends, isconnected by bolts 91 or otherwise (See FIG. 2) to plates 93 welded onextensions of the gear box 75. Adjacent its rearward end, the frame 71includes a generally vertically extending box frame member 95 which isconnected to the horizontally extending U-shaped member 89. Connected tothe upper sides of the box member are vertically extending exteriorpanels 97. The top of the box shaped member 95 supports a dashboard orinstrument panel 99. The bottom of the box shaped member 95 lies acrossthe bottom wall 37 of the body center section 35 and is suitablyattached thereto. Extending forwardly from the bottom of the box shapedmember 95 (See FIG. 3) is a channel member 101 which supports the engine73, and which, at its forward end, is bolted to the gear box 75.

TRANSMISSION SYSTEM The transmission system is powered by the engine 71and includes (See FIGS. 2 and 3) a housing 111 which constitutes boththe gear box 75 and an oil reservoir and which has opposing sides uponwhich are detachably mounted the hydraulic or hydrostatic transmissionunits 77. It is to be noted that one of the facets of the modularfeature of the invention resides in the ease of assembly and readyreplacement of the hydrostatic units 77 relative to the gear box 75.

Further in regard to the gear box construction which affords readyreceipt of the hydrostatic units, the gear box sides 113 each include(See FIG. 4) respective aligned openings 115 adapted to mate with thehydrostatic units 77 and to afford transfer of power from the gear box75 to the hydrostatic units 77. In addition, the gear box sides 113 alsoeach include respective openings 117 to afford passage of the outputshaft (still to be described) of the associated hydrostatic unit 77.Each such opening 117 has an outer counterbore 119 which mates with theassociated hydrostatic unit 77 and serves as a pilot to afford properalignment.

In addition, the gear box housing 111 includes means for detachablyconnecting thereto the hydrostatic units 77. While various arrangementscan be employed, in the disclosed construction, such means includes aplurality of posts or bosses 123 which extend from the respective sides113 of the gear box and receive bolts 125 which pass through a clampingmember 127 and through respective spacers 129. In turn, the clampingmembers 127 engage the hydrostatic units 77 to insure their properassembly on the gear box 75. Further details of the gear boxconstruction will be described after description of the hydrostaticunits 77.

Each of the hydrostatic units are generally of I identical conventionalconstruction and, as shown in FIG. 4, includes a housing 133 containing(See FIG. 6) a pump assembly 135 driven by (See FIG. 4) an input shaft137 having a male, splined outer end 139. Each hydrostatic unit 77 alsoincludes (See FIG. 6) a motor assembly 141 which drives an output shaft143 having its outer end machined to form a pinion 144 (See FIG. 4), andhydraulic passages 145 between the pump assembly 135 and the motorassembly 141.

The pump assembly 135 also conventionally includes a charge pump 149 anda pivotally mounted swash plate 151 which, depending upon its position,causes neutral, forward or rearward drive operation of the hydraulicallyconnected motor assembly 141. Fixedly connected to the swash plate 151is a control arm 153 which, when moved in one direction from a centeredor neutral position, provides forward drive operation of the motorassembly 141 at a speed which increases with increasing control armmovement from the neutral position and which, when moved in the otherdirection from the'centered or neutral position, provides reversedriveoperation of the motor assembly 141 at a speed which increases withincreasing movement of the control arm 153 from the neutral position.

In order to properly align the power input shaft 137 with the gear box75, the hydrostatic unit housing 133 includes a pilot sleeve portion 157which is concentric with the power input shaft 137 and which includes apcripheral annular groove receiving an O-ring 159 which serves asa'seal. When the hydrostatic unit is assembled to the gear box, thesleeve portion 157 extends into the opening 115 and the O ring 159provides a seal.

In addition, the hydrostatic unit housing 133 includes (See FIG. 4) apilot boss 161 in concentric relation to the motor output shaft 143.When the hydrostatic unit 77 is assembled to the gear box 75,, the boss16] is located in the counterbore 119 and a gasket is preferablyprovided therebetween to insure against a loss of oil.

Additional detailed information on the contruction of the hydrostaticunits employed in the disclosed construction can be found in theBulletin 9507 of the Sunstrand Corporation entitled HydrostaticTransmissions Tech Manual.

Means are provided in the gear box 75 for connecting the engine outputshaft 107 to the hydrostatic unit input shafts 137. While various meanscan be employed, in accordance with the invention, the gear box 75includes, as shown in FIG. 4, an input bevel gear 165 having anelongated hub 167 serving as a stub shaft which is supported by a pairof bearings, which extends exteriorly of the gear case 75 through asuitable opening, and which carries a coupling 171 connected to theengine output shaft 107. As shown in the drawings, one of the bearings169 also serves as a thrust bearing preventing axial movement of thegear 165 outwardly of the gear box 75. In addition, a suitable sealingarrangement 173 between the gear box and the stub shaft is provided.

Within the gear box, the bevel gear 165 is in mesh with another bevelgear 177 which includes a through axial bore 179 and an elongated hub181 supported for rotation by a combined radial and thrust bearing 183carried by the gear box housing 111. The gear hub 181 projectsexteriorly of the gear case 75 and within the sleeve portion 157 of theassociated hydrostatic unit and with the splined outer end 139 of thepump assem bly input shaft 137 received in the axial bore 179 of the hub181. Rotational driving connection is afforded by providing the hubportion of the bore 179 with an internal female spline which readilyreceives the male spline of the hydrostatic unit upon assembly of thehydrostatic unit 77 to the gear box 75. At its other end, i.c., at thegear end of the bore, the bore is counterbored at 185 to receive one endof a cross shaft 187 which is provided at both ends with a male spline.The end of the cross shaft 187 received in the bore 179 of the gear 177,is slid into the female spline of the gear so as to rotatably couple thecross shaft 187 to the gear 177. The cross shaft 187 has an axial lengthsuch that the other end thereof is received in a collar or sleeve 189which is, at least partially, located within the pilot sleeve portion157 of the other hydrostatic unit 77. The collar 189 is provided with aninternal female spline which drivingly receives the male splines on theadjacent ends of the cross shaft 187 and the input shaft 137 of theother hydrostatic unit 77. Thus, rotation of the input gear 165 servesto drive the pump assemblies 135 of both hydrostatic units 77 throughlubricated connections in the gear box 75. I

The already mentioned axle means are at least partially included in thegear box and connect the hydrostatic unit motor assemblies 141 to therespectively associated tracks 27. In this connection, when thehydrostatic units 77 are assembled to the gear box 75, the output shafts143 extend interiorly of the gear box through the openings 117 with thepinions 144 in meshed engagement with respective gears 195 which arelocated within the gear box 75. The gears 195 are respectively fixed onthe respective axle shafts 83 which are suitably journaled in generalaxial alignment by respective radial and thrust bearings 197 carried bygear case extensions or sleeves 199 which are suitably fixed as bywelding or otherwise to the housing 11 1 and constitute portionsthereof. inwardly of their outer ends, the axle sleeves 199 havesuitably fixed thereto, as by welding or otherwise, the generallyupright plates 93 which respectively include ears suitably fixed, as bythe bolts 91 or otherwise, to the forward ends of the forwardly openU-shaped frame member 89. During assembly of the power group to the body13, the beforementioned L-shaped closure members 85 are suitably fixed,as by screws or bolts, to both the plates 93 and to the margins of thebody 13 around the body openings 55 to provide the body with watertightintegrity.

It should be noted that while the lateral distance between the outerends of the axle shafts 83 is greater than the distance between the sidewalls 43 of the body center section 35, the distance between the outerextremities of the deck parts 59 of the body openings 55 is greater thanthe lateral distance between the outer ends of the axle shafts 83. Thus,the deck parts 59 of the body openings 55 facilitate placement of thepower generating and transmission group 15 in the body center section 35and, ultimately, assembly of the power group 15 to the body 13.

At the ends of the axle sleeves 199, suitable seals 201 are providedbetween the sleeves 199 and the axle shafts, 83 to prevent entry of dirtor moisture.

After assembly of the power group 15 to the body 13, the sprockets 25(still to be described in detail) are keyed and fixed to the ends of theaxle shafts 83. If not already assembled to the body 13, the tracksuspension group 17 is also assembled to the body. Thereafter, the rearbogie assemblies, still to be described, are pivoted to permit placingof the endless track 27 around thc sprockets 25 and around the bogiewheels (also still to be described) with the interior lugs of the tracksbetween the bogie wheel discs.

From the foregoing, it is apparent that, depending upon the setting ofthe respective swash plates 151, input of power from the engine 73 tothe gear box 75 can selectively result in forward, neutral or rearwarddrive conditions for each track 27.

OIL CIRCULATION SYSTEM The hydraulic components of the power generatingand transmission group 15 are hydraulically assembled together toprovide an oil circulation system which is shown diagrammatically inFIG. 6. In accordance with the invention, one of the features of the oilcirculation system is the employment of the gear case 75 as a reservoiror sump for the hydraulic oil used by the hydrostatic units 77. Anotherof the features resides in the arrangement for providing an oil flowconnection be tween the hydraulic motor assembly 141 of each hydrostaticunit 77 and the gear case 75. More specifically, as shown in detail inFIG. 4, oil discharged from each motor assembly 141 flows throughopenings 205 adjacent to the motor output shaft 143 and into the gearcase 75 which, as noted, serves as a sump or reservoir. Such oil in thereservoir, serves to also lubricate the gearing and bearings in the gearbox or casing 75.

Oil flows (See FIG. 6) from the gear box or case 75 through a dischargeconduit or duct 207 to the radiator or heat exchanger 79 which issupported by the frame 71 above the gear case 75 in the location shownin the top portion of FIG. 3. Oil is pumped from the radiator 79 by thecharge pump 149 of the hydrostatic units and through symmetrical branchlines or ducts 211 which communicate with respective filters 213associated with the respective pump assemblies of the hydrostatic units77. Within the hydrostatic units, oil flows from the filters 213 throughducts 215 to the charge pumps 149 and thence through passages 203 to thepump assemblies 135. From the pump assemblies 135 oil flows through theinternal passages to the motor assemblies 141 from which the oil isdumped through the openings 205 into the reservoir or sump formed by thegear case 75 for subsequent cooling and recirculatron.

HYDROSTATIC TRANSMISSION CONTROL for rocking movement about its ownaxis. While vari- I ous arrangements can be employed to mount the stickfor movement about the just mentioned axes, in the disclosedconstruction, as shown in FIGS. 7, 8 and 9, the U-shaped frame member 89has fixed thereto a pair of opposed brackets 229 which, adjacent one endthereof, pivotally support the forwardly and vertically extending legs231 of a U-shaped bracket 233 having a web 235. Projecting rearwardlyand horizontally from the web are spaced upper and lower yoke members237 and 239 having respectively aligned apertures. Extending through thealigned apertures in the yoke members 237 and 239 for rotatationalmovement relative to the yoke members and to the frame 71 is the controlstick 225.

Various means can be employed to prevent axial movement of the controlstick 225 relative to the U- shaped bracket 233. In the disclosedconstruction, such means includes an upper L-shaped member 241 havingone leg welded or otherwise fixed to the control stick above the upperyoke member 237 and having the other leg extending downwardly in spacedgenerally parallel relation to the control member 225 rearwardly of thefree end of the upper yoke member 237. Connected to the free leg of theupper L-shaped member is one leg of a lower L-shaped member 243 having asecond leg 245 extending perpendicularly to the control stick just belowthe bottom yoke member 239 and having an opening receiving the lower endof the control stick 225. Fixation of the upper L-shaped member 241 tothe control stick 225 and location of the legs immediately above andbelow the yoke members 237 and 239 affords pivotal movement of thecontrol stick 225 while preventing axial movement.

Above the U-shaped bracket 233, the control stick 225 is provided with aplate 251 which is inclined to the axis of the control member 225 andwhich has pivotal connections with a pair of links 253 which arerespectively pivotally connected to the control arms 153 of thehydraulic transmission units 77. The links can be constructed as shownin US. Pat. application Ser. No. 821,214. When the control stick 225 isin its neutral position, the pivotal connections between the links 253and the plate 251 are located at the same lateral distance from the axisof the control stick 225 and at the same distance from, but on oppositesides of, a fore and aft plane extending through the axis of thecontrolstick 225.

The upper end of the control stick 225 extends through an elongated slot255 in the dashboard 99 and, as previously mentioned, has fixed, at thevery top, the cross bar 227.

In operation, forward movement of the control stick 225 will displacethe links 253 forwardly so as to swing forwardly the control arms 153 ofboth hydrostatic transmission units 77, thereby actuating the swashplates 151 so as to provide pumping operation to efi'ect forward driveof the motor assemblies 141. As previously noted, the speed at which thehydraulic motor assemblies 141 operate can be increased by increasingthe displacement of the control arms 153 by pushing the stick 225further forward. Pulling the stick 225 rearwardly toward the operatorfrom a position advanced forward from the neutral position will decreasethe forward speed output of the hydrostatic transmission units 77 untilthe neutral position of the control arms 153 is again achieved. Furtherrearward movement of the control stick 225 will cause the swash plates151 to operate the hydraulic motor assemblies 141 in the reversedirection with increasing speed as the control stick 225 is displacedfurther rearwardly from its neutral position. Twisting of the controlstick 225 about its own axis will cause differential movement of thecontrol arms 153 such as to swing one control arm in one direction andswing the other control arm in the opposite direction, thereby operatingthe motor assemblies 141 at differing speeds and, possibly in dif ferentdirections, so as to cause turning movement of the vehicle. If thecontrol stick 225 is in neutral position when the control stick istwisted on its own axis, one motor assembly 141 will run in forward andthe other in reverse, thereby permitting the vehicle to turn uponitself. lf the control stick 225 is advanced from its neutral position,twisting of the control stick will cause one motor assembly 141 to runfaster in whatever direction it was going and will cause: the othermotor assembly 141 to run slower in the initial direction and, perhaps,to even reverse direction.

REVERSE LOCK-OUT The T-bar control stick 225 of the disclosed vehiclehas considerable sensitivity and it can be undesirable to permit theoperator to displace the control stick, with out some sort of notice orinterruption, from forward through neutral and into reverse. Moreparticularly, when the operator senses that he is going too fast andwishes to slow up, it is undesirable to permit the operator to pull backon the control stick 225 to such extent as to shift into reverse drive.Accordingly, a releasable reverse drive lock -out system is provided.

In accordance with the invention, the reverse lockout arrangementincludes a downwardly extending lip 259 at the lower end of the L-shapedbracket 243 and a pivotally mounted stop member 261 having a block ingportion 263 which is normally in a blocking position in the path of lipmovement upon control stick movement from neutral in the direction whicheffects reverse drive. More particularly, the brackets 229 which supportthe control stick 225 also pivotally supports the stop member 261 at265. Fixedly connected to and forming a part of the stop member 261 isan L-shaped arm 267 which is pivotally connected at its outer end to arod 269. which extends upwardly through a slot in the dashboard 99 andhas a knob 271 at its upper end. The stop member 261 is releasably urgedto the blocking position by a spring 273 which is connected to the stopmember 261 and to the lower surface of the dashboard 99.

In operation, when it is desired to operate in reverse, the operatordepresses the knob 271 so as to swing the block portion 263 downwardlyabout its pivotal support at 265 and out of the possible path ofmovement of the lip 259. when the block portion 263 is so de pressed,the control stick 225 can then be moved to displace the lip 259 throughthe space previously occupied by the block portion 263 and to bringabout a reverse drive condition. Continued operation in reverse drive ispermitted without holding the knob 271 in depressed position because thelip 259 prevents the block portion 263 from returning to blockingposition. However, when the control stick 225 is shifted back toneutral, the spring 273 automatically causes return of the block portion263 into position preventing reverse drive operation.

THE MOTOR HOOD After assembly of the power generating and transmis siongroup 15 to the body 13, the power group is covered by the hood or cover23 which includes a front hood section 279 located forwardly of thedashboard 99 and extending to almost the front of the body. As will bereferred to hereinafter, the forward hood section 279 includes sidewalls 281 and a top wall 283, and several vents which form part of theair cooling system.

The hood 23 also includes a rear section 285 located rearwardly andunderneath the dashboard. As will be described in greater detail, therear hood section 285 also serves as a component of the air coolingsystem.

Any suitable means can be employed to releasably fasten the motor hoodsections to the power group frame and vehicle body.

RADIATOR AND ENGINE COOLING SYSTEM The disclosed vehicle includes a dualflow arrangement for separately inducting air for cooling of thehydraulic system and for cooling of the engine 73. More specifically,the forward motor hood section 279 has,

on each side 281, a forward screened opening or air inlet 287 throughwhich outside air is sucked or pumped interiorly of the hood 23.Supported by the frame 71 are baffle means which are provided to preventthe incoming air from flowing rearwardly or downwardly from the airinlets 287 and to convey the air solely to the top surface of theradiator 79.

More specifically, as seen in FIGS. 2, 3 and 4, such baffle meansincludes a vertical baffle 291 which is supported by the frame 71 andextends generally from the bottom wall 37 of the body 13 to the fronthood section 279 and which divides the center body section 35 into aforward compartment containing the gear case 75 and into a rear or aftercompartment containing the engine 73. Such baffle means also includes(See FIG. 2) a horizontal baffle 293 which is supported by the frame 71and/or the body 13 and which extends, forwardly from the vertical baffle291 to the front of the body 13 and from the deck walls 49 to theradiator 79, thereby dividing the area in front of-the vertical baffle291, i.e., the forward compartment, into a lower gear case compartmentand an upper inlet air compartment which conducts air from the forwardair inlets 287 to the radiator 79 and which is located between thehorizontal baffle 293 and the front hood section 279 and forwardly ofthe vertical baffle 291.

After passing through and cooling the radiator 79, the incoming air thenpasses downwardly into the gear case compartment and over the gear case75. The air is then drawn (See FIG. 4) through an opening 295 in thevertical baffle 291 by a fan 297 which is concentrically arranged withthe opening and which is carried on a coupling 299 connected to theengine output shaft 107 and connected through the opening 295 to thegear case coupling 171.

Air for engine cooling is drawn inwardly of the front hood sectionthrough two rearwardly located upper screened inlets 303. Such incomingair is directed rearwardly under the dashboard 99 by a baffle 305 (Seeupper portion of FIG. 3) which is supported by the frame 71 and extendstransversely and generally horizontally rearwardly from the lower edgeof the inlets 303. From under the dashboard 99, the air flows downwardlyand then reversely and into the engine compartment. Rearward diffusionof the air is prevented by the rear hood section 285 which extends fromthe dashboard 99 to the bottom wall 37 of the center body section 35 andbetween the side walls 43 of the center body section. Such downward airflows past the carburetor air inlet 307 to supply combustion air to theengine 73 and is sucked toward the engine by an engine fly-wheel fan309. Air discharged by the engine flywheel fan 309 travels forwardlyover the engine cylinders into the forward part of the enginecompartment rearwardly of the vertical baffle 291. Such incoming enginecooling air is mixed with the air delivered rearwardly from the gearcase compartment through the opening 295 by the fan 297. Such intermixedair then exits from the engine compartment through rearward side vents311 in the side walls 281 of the front hood section 279.

THE DRIVE SPROCKET Attached to the outer ends of each of the axle shafts83 extending from the power group 15 is one of the drive sprockets 25which are constructed in accordance with the invention. The sprockets 25are ar-- ranged to provide a maximum open area for discharge of snow,mud, or the like, which otherwise might collect on the inner surfaces ofthe drive sprocket while, at the same time, maximizing engagement of thesprocket with the track to afford effective and reliable pullingoperation.

The drive sprocket shown in FIGS. 4 and 5 is constructed by welding orotherwise unitizing two sprocket sections 315 which are generally ofidentical construction. Each sprocket section 315 includes a hub 317having a central keyed opening 319 affording attachment to theassociated axle 83. Extending from the hub in angularly spaced relationand in radially outwardly and obliquely inclined relation to the axis ofintended rotation are a plurality of spokes 321. While more than threespokes can be used, the illustrated construction including threeequiangularly spaced spokes 321 is preferred, as a maximum of open arearesults.

Connected to the outer ends of the spokes 321 is an annular portion ormember 323 which extends normal to the axis of the sprocket 25 and hasan inner or side surface spaced axially from the adjacent end of the hub317. In addition, the annular member 323 has an inner periphery spacedradially outwardly from the outer periphery of the hub. As aconsequence, the sprocket 25 is open both axially and radially betweenthe hub and the annular member to afford easy escape of debris whichmight otherwise tend to accumulate within and about the sprocket.

Extending axially from the annular member 323 is a circumferentialseries of equiangularly spaced sprocket lugs or teeth which engage thelugs on the inner surface of the track to effect track movement inresponse to sprocket rotation. While the number of sprocket teeth can bevaried, in the disclosed construction, each sprocket section 315includes nine teeth 325. In cross section, each of the teeth 325 isgenerally of half-moon shape and is located with the resulting concavityopening radially toward the hub 317.

It is to be especially noted that even when the sprocket sections 315are assembled, as by welding together, the angularity and spacing of thespokes 321, together with the locaton of the annular members 323 offersa maximum of escape area for mud and snow. Specifically, mud and snowcan exit from within the sprocket in the radially outward direction andin both axial directions.

TRACK SUSPENSION GROUP The track suspension group 17 can be assembledin- 13 dependently of the body 13 and the power generating andtransmission group 15 and subsequently assembled to the body 13independently of assembly of the power generating and transmission group15 to the body 13. In accordance with the invention, the tracksuspension group 17 includes a frame or support 341 having a pluralityof structural cross members which are respec tively and individuallylocated in the respective downwardly open channels 45 formed in thebottom of the body. While various arrangements are possible, in thedisclosed construction (See the lower portion of FIG. 3), the frame 341includes a forward cross member 343 and an intermediate cross member 345and a rearward cross member 347.

The cross members 343, 345 and 347 are integrated into the frame 341 bylongitudinal beams. While various arrangements can be employed, in thedisclosed construction, two beams 349 are employed, which beams arerespectively and suitably connected to the opposite ends of the crossmembers 343, 345 and 347. If desired, the beams could be connected tothe cross members inwardly of the ends thereof.

The track suspension group 17 is connected to the body 13 to maintainthe body watertight'and so as to locate the cross members 343, 345 and347 in the downwardly open channels 45 by means (See FIGS. 10, 11 and12) in the form of plates 351 which are welded or otherwise fixed to thecross members and which are adapted to span the ends of the channels 45and con tact the exterior surface of the side margins around the channelends. Suitable means, such as screws or bolts 353, applicable from theexterior, can be employed to attach the plates 351 to the side walls 43of the body 13. In the specifically disclosed and preferredconstruction, two spaced plates are employed on each cross member andeach plate 351 forms one leg of an L- shaped bracket having an inwardlyextending leg 355 t in engagement with and supporting the under-surfaceof the bottom wall 37 of the body 13 on each side of the applicablechannel 45. The area of the plates 351 and the surface contact betweenthe plates 351 and the body 13 is such that, even if through bolts areused to connect the plates to the body, a watertight connection can bereliably obtained and maintained. If desired, the inwardly extendinglegs 355 can also be bolted or 0th erwise fastened to the body 13.

Carried along each side of the track assembly frame 341 and under theadjacent deck wall 49 is a track suspension system. Each of thesuspension systems includes inner and outer front bogie wheels 357 and359 (See FIG. 12), intermediate inner and outer bogie wheel assemblies363 (See bottom portion of FIG. 3), a rear bogie wheel assembly 367 andinner and outer rearward idler bogie wheels 371 and 373 (See FIG. 15).As each suspension system is identical, only one will be described.

Located at the front end of the track suspension frame 341 are the innerand outer first or front rotatable bogie wheels 357 and 359 which areseparately supported in transversely adjacent and generally axiallyaligned relation to each other for rotational movement about theirrespective centers and for limited pivotal movement about the forwardcross member 343. More particularly, the inner and outer bogie wheels357 and 359 are generally of the same construction and, as shown best inFIG. 14, comprise a pair of transversely spaced discs 381 having alaterally outwardly extending thin peripheral lip 383. The discs 381 arekeyed or otherwise fixed to a shaft having a central bearing 387received in a sleeve 389 which includes, at each end, a counterborereceiving a seal member 393 which prevents entry of dirt or moistureinto the bearing 387. In addition, each of the discs 381 is providedwith a counterbored inwardly extending hub portion 395 which re ccivesthe end portions of the sleeve 389 to further as sist in excluding dirtor moisture.

While various arrangements can be employed, in the disclosedconstruction, in order to permit lessening of shock upon contact of thetrack 27 with large obstacles and to ease passage of the vehicle overlarge obstacles, means are provided to support the front bogie wheelswhile, at the same time, affording resilient rearward swinging movement,thereby decreasing the angle of the upwardly and forwardly extendingtrack to the ground.

As the arrangement for supporting each of the inner and outer frontbogie wheels 357 and 359 is essentially the same, only the arrangementfor supporting the outer front bogie wheel 359 will be described.

More particularly in the disclosed construction, as shown in FIGS. 12,13 and 14, the outer front bogie wheel 359 is mounted for resilientswinging movement about the axis of the front cross member 343 by meansincluding a generally vertically extending support bar 399 and a rubbertorsion bushing assembly 401. Still more particularly, the torsionbushing assembly includes an inner sleeve 403 which is telescoped ontothe front cross member 343 into proper position and are suitably spacedand fixed thereto. The outer periphery of the sleeve is cylindrical andhas bonded thereto a ring or annulus 405 of rubber or other rubber-likeelastomeric material. Bonded to the outer cylindrical surface of thering 405 is a cylindrical metallic jacket 407 having a pair ofdiametrically radially outwardly extending ears 409. The bushingassembly is received in an upwardly open cradle 411 which is welded orotherwise suitablyconnected to the upper end of the support bar 399 andwhich has a pair of diametrically extending tabs 413 which mate with theears 409 and are suitably connected thereto, as by belts or the like. Atits lower end, the support bar 399 is welded to the bogie wheel sleeve389. r

The extent of the resilient pivotal movement permitted to the frontbogie wheels 357 and 359 is determined by the torsional resistance ofthe rubber ring 405.

Intermediate 'its ends, the traclc suspension system further includesintermediate inner and outer bogie wheel assemblies 363 each havingrotatably mounted second and third bogie wheels 419 which are generallyof the same construction as the front bogie wheels and which arearranged and supported such that the axes of the inner second and thirdbogie wheels are generally respectively laterally aligned with respectto the axes of the outer second and third bogie wheels.

As in the case of the front bogie wheels, the intermediate inner andouter bogie wheel assemblies 363 are separately supported. Each of theintermediate inner and outer bogie wheel assemblies 363 includes meansfor supporting the bogie wheels for resilient up and down movement andfor pivotal movement about a transverse axis located intermediate thesecond and third bogie wheels. The construction of the inten'nediateinner and outer assemblies is generallythe same.

To achieve the foregoing support, the sleeves of the outer bogie wheelsare suitably connected, as by clamps 423, to the ends of a leaf spring425 which, intermediate the ends thereof, is suitably fixed, as by aclamp 427, to the web 429 of an inverted U-shaped bracket 431 havingupwardly extending legs supporting a fixed pivot 433. In turn, the fixedpivot 433 is received in a bushing or sleeve 435 which is locatedbetween the bracket legs and fixed to the lower end of a post 437depending fixedly from the intermediate c'ross member 345.

While separate pivots have been provided for each of the intermediateinner and outer bogie wheels assem blies 363, a single pivot membercould be employed to support both inner and outer bogie wheel assembliesand still provide the same functional result. Thus, the intermediatebogie wheel assemblies 363 have independent pivotal movement about anaxis extending transversely between the second and third bogie wheelsand, in addition, each of the bogie wheels is supported so as to affordresilient up and down movement relative to the other bogie wheel of eachassembly, as well as rotative movement about its own axis.

Supported on the rear cross member 347 is the rear bogie wheel assembly367 which includes fourth and fifth inner rotatable bogie wheels 445 andfourth and fifth outer rotatable bogie wheels 445 which are respectivelylocated in transversely adjacent and axially aligned relation to thefourth and fifth inner bogie wheels. Each of the inner and outer fourthand fifth bogie wheels 445 is of like construction to the front bogiewheels. The fourth and fifth outer bogie wheels are integrated into anouter bogie wheel sub-assembly 447 by a strut or rocker bar 449 which iswelded or otherwise fixed at its ends to the sleeves of the fourth andfifth outer bogie wheels. A similar rocker bar 451 is fixed so as tointegrate the fourth and fifth inner bogie wheels into an innersub-assembly 453.

In order to provide for independent movement of the inner and outerbogie wheel sub-assemblies 447 and 453 so as to provide bothlongitudinal and transverse flexibility, the inner and outer bogie wheelsubassemblies each include mounting means affording pivotal movementabout aligned axes intermediate the fourth and fifth bogie wheels.

While various arrangements can be employed to separately afford pivotalmovement for the inner and outer bogie wheel sub-assemblies 447 and 453,the arrangement for both bogie wheel sub-assemblies is the same. Onlythe arrangement at the outer bogie wheel assembly, as shown in FIG. 15,will be described in detail.

More particularly, the outer bogie wheel subassembly 447 has fixedthereto, as by welding or otherwise, a bushing or sleeve 457 which islocated centrally of the associated bar 449 and which receives a pivotpin 459. In turn, the pivot pin 459 is fixed by welding or otherwise tothe spaced downwardly extending legs 461 of a U-shaped bracket orconnecting member 463 which straddles the sleeve 457 and which has aconnecting web 465 located above the bar 449.

Also forming a part of the connecting bracket 463 is a right angleflange 467 which is welded or otherwise suitably fixed to the web 465and which serves as a point of assembly to a cross bar or member 469having welded. or otherwise suitably fixed to each end. a connectingplate or flange 471 which are respectively fixed, as by bolts 473, tothe connecting brackets 463 associated with each of the inner and outerbogie wheel sub-assemblies 447 and 453.

Connected to the undersurface of the cross bar 469 for support thereofis a hollow tube 475 which is of rectangular cross-section and istelescoped on the rear end of a generally horizontal extending rear endportion 477 of an arm 479 which also includes a somewhat enlargedupwardly bent portion 481 connected to the rear cross member 347. Meansare provided to maintain proper tension in the track. Variousarrangements, including screw means can be employed. In the specificallydisclosed construction, one or more shims 483 are located in telescopicrelation on the rear end portion 477 of the arm 479 between thetelescoping tube 475 and the upwardly inclined arm portion 481. As shownin FIG. 15, a cotter pin 485 can be employed adjacent to the rearwardend of the rear end portion 477 to pre vent disconnection of thetelescoping tube 475 and the rearward end portion 477 of the arm 479.

In order to permit the endless tracks 27 to be slipped over theassociated bogie wheels and sprockets, each rear bogie wheel assembly367 is fixed to the rear cross member 347 so as to afford pivotalmovement therebetween. While various means can be utilized to providesuch pivotal construction, in the disclosed construction, the upperendof each arm 479 has fixed thereto, See FIG. 16, a bushing 49] whichreceives a pivot pin 493 extending between a pair of spaced parallelplates or brackets 495 suitably fixed, as by welding or otherwise, tothe rear cross member 347 in adjacent outward relation to the opposedsides of the associated arm 479.

Means are provided to locate the arm 479 in proper angular relation tothe rear cross member 347 and to releasably retain the arm 479 in suchangular relation to the rear cross member 347. While variousarrangements can be employed, in the disclosed construction, such meansincludes, at the rearward end of the plates 495, upper and lower bolts497 and 499 which extend between the parallel plates above and below thearm 479 so as to confine the arm in proper angular relation ship to thecross member 347. However, in order to swing the arm 479 downwardly,i.e., counterclockwise, as shown in FIG. 16, about the pivotalengagement on the pin 493, and to thereby facilitate slipping of theassociated track over the sprocket and bogie wheels, the lower bolt 499is removable.

Means are provided to establish a normal position for each of the rearbogie wheel sub-assemblies 447 and 453, to independently permitresilient pivotal movement of each sub-assembly relative to said normalposition and to limit pivotal movement of each subassembly from thenormal operating position. As the arrangement provided for each of theinner and outer bogie wheel assemblies 447 and 453 is generallyidentical, only the construction associated with the outer bogie wheelsub-assembly 447 will be described.

While various arrangements can be employed to establish a normaloperating position and to afford resilient pivotal movement relative tosaid normal position, in the disclosed construction, an elastomeric orrubber mount or spring 503 is connected between the connect ing flange471 of the bogie wheel assembly cross bar 469 and the outer sub-assemblyfore and aft bar 449. More particularly, the resilient mount 503comprises a cylindrical body of rubber or other like material havingimbedded therein separate threaded studs which extend from the oppositeends of the cylindrical body.

One of said studs extends through and is bolted at 505 to a forwardextension 507 of the connecting flange 471 at the adjacent end of therear bogie wheel cross bar 469. The other stud extends through and isbolted at 509 to an upright bracket 511 which is welded or otherwisefixed to'the outer fore and aft beam 449 of the outer sub-assembly 447.

Accordingly, each sub-assembly 447 and 453 tends to assume a normalposition in which the rubber mount 503 is not under stress. However, therubber mount 503 will deform in shear to offer resilient pivotal movement away from the normal position and to accommodate track flexure inconformance with ground conditions.

While other means can be employed, pivotal movement from the normalposition in the counterclockwise direction, as shown in FIG. 16, isessentially prevented by engagement of the rear undersurface of the web465 with the bogie sub-assembly fore and aft beam 449. Pivotal bogiesub-assembly movement in the clockwise direction from the neutralposition is limited by engagement of the sub-assembly fore and aft beam449 with (See FIG. a bent ear or tab 515 at the forward extremity of theconnector flange extension 507 to which the rubber mount 503 isconnected. Thus, each of the rear bogie wheel assemblies 367 includesinner and outer bogie wheel sub-assemblies 447 and 453 which provideflexible support to the track in both the longitudinal and transversedirections.

Also forming a part of each track suspension system are a pair of upperrearward inner and outer idler bogie wheels 371 and 373 which areconstructed in generally the same manner as the front bogie wheels. Eachof the rearward idler bogie wheels are respectively fixed (as shown bestin FIGS. 15 and 16) by separate arms 521 which, at one end, are weldedor otherwise suitably secured to the rear cross member 347 and, at theother end, are suitably fixed to the associated bogie wheels as byemployment of respective clamps 523 encircling the respective bogiewheel sleeves.

It should be noted that, generally speaking, all of the inner bogiewheels are generally longitudinally aligned and that all of the outerbogie wheels are similarly longitudinally aligned.

THE TRACKS The tracks 27 are of endless construction of rubber or othersimilar material and include, on the outer surface, longitudinallyspaced transverse treads 531 (See FIGS. 12 and 18), as well as rows oftransversely spaced studs or buttons 532 which are located interme diatethe transverse treads 531. In addition, the outer surface of the tracks27 is provided along both longitudinal edges with a rib or margin 533which is raised to an extent less than the height of the treads 531 andthe studs 532. On its inner surface, each track 27 includes a pair oflongitudinally extending parallel series of lugs 535 which are engagedby the sprocket teeth 325 and extend within the spaced discs 381 of thebogie wheels.

It is especially noted that the studs 532 assist the margins 533 inpreventing lateral slippage of the tracks in snow or mud or the like. Inaddition, the studs 532 are transversely located so as to be inlongitudinal alignment with the outer edges or rims 383 of the-bogiewheels. Thus, the studs 532 are located in laterally outwardly adjacentrelation to the lugs 535 but on the opposite side of the track. Locationof the studs 532 in alignment with the rims 383 of thehogie wheel discs38] provides a smoother, quieter ride as the studs 532 prevent anytendency toward track flexure which might otherwise occur as aconsequence of travel of the bogie wheels relative to flat ground.

In general, the tracks 27 are generally unbroken to obtain the greatestpossible load supporting surface and are flexible in both thelongitudinal and transverse direction. Such flexibility is illustratedin FIG. 12 wherein the right side of the track is shown passing over anobject 537 which does not extend for the full width of the track.

In addition, it is noted that the diameter of the bogie wheel discs 381is so related to the size or dimensions of the lugs 535 such that, atleast portion of two lugs are transversely retained within the paralleldiscs 381 of .each bogie wheel at all times, thereby assuring propermaintenance of the track on the track suspension system.

Various of the features of the invention are set forth in the followingclaims.

What is claimed is: I

1. A vehicle comprising a frame, an engine mounted on said frame andincluding a crankshaft, a gear case mounted on said frame, a pair ofhydrostatic transmissions respectively detachably mounted on the opposedsides of the exterior of said gear case and each including an inputshaft extending into said gear case, an output shaft extending into saidgear case in parallel relation to said input shaft, a pivotally mountedswash plate to provide for swash plate movement in response to controlarm movement whereby to locate said swash plate in positions affordingneutral, forward and reverse drive conditions of said transmissions,power input means connected to said crankshaft exteriorly of said gearcase and connected to said hydrostatic transmission input shaftsinteriorly of said gear case, power output means connected interiorly ofsaid gear case to said hydrostatic transmission output shafts andincluding a pair of axle shafts, first and second sprockets fixedrespectively on said axle shafts, first and second endless flexibletracks respectively trained about said first and second sprockets, andmeans for moving said control arms to provide for coordinated speed anddirection control of said tracks.

2. A vehicle comprisinga frame, an engine mounted on said frame andincluding a crankshaft, a gear case mounted on said frame, a pair ofhydrostatic transmissions respectively detachably mounted on the opposedsides of the exterior of said gear case and each including an inputshaft extending into said gear case, an output shaft extending into saidgear case in parallel relation to said input shaft, a pivotally mountedswash plate, and a control arm connected to said swash plate to providefor swash plate movement in response to control arm movement whereby tolocate said control arm and swash plate in positions affording neutral,forward and reverse drive conditions of said transmissions, power inputmeans connected to said crankshaft exteriorly of said gear case andconnected to said hydrostatic transmission input shafts interiorly ofsaid gear case, power output means connected interiorly of said gearcase to said hydrostatic transmission output shafts and including a pairof axle shafts, first and second sprockets fixed respectively on saidaxle shafts, first and second endless flexible tracks respectivelytrained about said first and second sprockets, a control member,

means mounting said control member on said frame for movement about afirst axis, means mounting said control member on said frame formovement about a second axis at right angles to said first axis, a pairof links connected respectively to said control arms and to said controlmember at the same distance from and on opposite sides of said firstaxis and at the same distance from and on the same side of said secondaxis, a stop including a blocking portion, means mounting said stop onsaid frame for movement of said blocking portion relative to a positionin the path of control member movement about one of said axes to limitcontrol member movement about said one axis to thereby prevent movementof said control arm to reverse drive positions, and a spring connectedto said stop for biasing said blocking portion to said position.

3. A vehicle comprising a frame, an engine mounted on said frame andincluding a crankshaft, a gear case mounted on said frame, a pair ofhydrostatic transmissions respectively detachably mounted on the opposedsides of the exterior of said gear case and each including an inputshaft extending into said gear case, an out put shaft extending intosaid gear case in parallel relation to said input shaft, a pivotallymounted swash plate, a control arm connected to said swash plate toprovide for swash plate movement in response to control arm movementwhereby to locate said swash plate in positions affording neutral,forward and reverse drive conditions of said transmissions, andhydraulic fluid passages, power input means connected to said crankshaftexteriorly of said gear case and connected to said hydrostatictransmission input shafts interiorly of said gear case, power outputmeans connected interiorly of said gear case to said hydrostatictransmission output shafts and including a pair of axle shafts, ahydraulic fluid radiator mounted on said frame and including hydraulicfluid passages, a hydraulic fluid circulation system including hydraulicconnections coupling said transmission passages, said radiator passagesand said gear case in a closed series hydraulic circuit, first andsecond sprockets fixed respectively on said axle shafts, first andsecond endless flexible tracks respectively trained about said first andsecond sprock ets, and means for moving said control arms to provide forcoordinated speed and direction control of said tracks.

4. A vehicle comprising a gear case, an engine connected to said gearcase and including a crankshaft, a pair of transmissions respectivelydetachably mounted on the opposed sides of the exterior of said gearcase and each including an input shaft extending into said gear case, anoutput shaft extending into said gear case in parallel relation to saidinput shaft, and a control arm operable to provide neutral, forward andreverse drive conditions, power input means connected to said crankshaftexteriorly of said gear case and connected to said transmission inputshafts interiorly of said gear case, and power output means connectedinteriorly of said gear case to said transmission output shafts andincluding a pair of co-axial power output shafts extending exteriorly ofsaid gear case.

5. A vehicle in accordance with claim 4 and including a frame andwherein said gear case and said engine are mounted on said frame,wherein said pair of transmissions comprise hydrostatic transmissionseach also including a pivotally mounted swash plate, and whereinsaid'control arm is connected to said swash plate to provide for swashplate movement in response to control arm movement whereby to locatesaid swash plates in positions affording neutral, forward and reversedrive conditions, and further including first and second sprockets fixedrespectively on said power output shafts, first and second endlessflexible tracks respectively trained about said first and secondsprockets, and means for moving said control arms to provide forcoordinated speed and direction control of said tracks.

6. A vehicle comprising a frame, an engine mounted on said frame andincluding a crankshaft, a gear box mounted on said frame, a pair ofhydrostatic transmissions respectively detachably mounted on the opposedsides of the exterior of said gear box and each including an input shaftextending into said gear box, an output shaft extending into said gearbox in parallel relation to said input shaft, a control arm operable toprovide neutral, forward and reverse drive conditions, and hydraulicfluid passages, a power input means-connected to said crankshaftexteriorly of said gear box and con-' nected to said hydrostatictransmission input shafts interiorly of said gear'box, power outputmeans connected interiorly of said gear box to said hydrostatictransmission output shafts and including power output shafts extendingexteriorly of said gear box, a hydraulic fluid radiator mounted on saidframe and including hydraulic fluid passages, and a hydraulic fluidcirculation system including hydraulic connections coupling saidtransmission passages, said radiator passages and said gear box in aclosed series hydraulic circuit.

7. A vehicle comprising a body including a bottom wall, a front wallextending from said bottom wall, opposed side walls extending from saidbottom wall and from said front wall, a power assembly including a frameconnected to said body and including a dashboard, an engine mounted. onsaid frame below said dashboard and including an air fan arranged todirect air over said engine from the rear thereof toward the frontthereof, a gear box mounted on said frame, a pair of hydrostatictransmissions detachably mounted on the exterior of said gear boxandeach including hydraulic passages, an input shaft extending into saidgear box, an output shaft extending into said gear box in parallelrelation to said input shaft, and a control arm operable to provideneutral, forward and reverse drive conditions of said transmissions,power input means extending exteriorly of said gear box and connected tosaid transmission input shafts interiorly of said gear box, power outputmeans connected interiorly of said gear box to said transmission outputshafts and including power output shafts extending exteriorly of saidgear box, a hydraulic fluid radiator mounted on said frame and includinghydraulic fluid passages, a hydraulic circulation system includinghydraulic connections coupling said transmission passages, said radiatorpassages and said gear box in a closed series hydraulic circuit, a hooddetachably connected to said body and comprising a front sectionincluding side walls and a top wall and extending forwardly of saiddashboard above said power assembly and to adjacent to said body fromand side walls, and a rear section extending vertically from saiddashboard to said bottom wall and between said side walls, a firstbaffle supported by said body and located between said engine and saidgear box and extending generally vertically from said bottom wall tosaid front hood section and between said body side walls to define aforward compartment, and

a rear compartment containing said engine and closed at the rear by saidrear hood section, said first baffle including an opening therein, asecond baffle supported by said body and extending generallyhorizontally across said forward compartment from said radiator to saidfirst baffle and to adjacent said body front and side walls to dividesaid forward compartment into a lower compartment containing said gearbox and an upper air intake compartment, a front air inlet located inone of said front hood section side walls and communicating with saidair intake compartment, an air vent located in one of said front hoodsection side walls and communicating with said compartment containingsaid engine, a rear air inlet located in said front hood section topwall, baffle means supported by said frame and extend ing rearwardly ofsaid rear air inlet for conducting air from said rear air inletrearwardly and above said engine and underneath said dashboard forcommunica" said front air inlet, through said intake compartment,

through said radiator, through said compartment containing said gearbox, and through said opening into said compartment containing saidengine for discharge through said air vent.

UNITED STATES PATENT OFFICE QERTIFICATE OF CQRRECTION Patent NO-3.776.325 Dated December A, 19$? Inventofls) Herbert J Ja-spersen It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 18, line 30 After "plate", insert----,and a control arm connectedto said squash plate--.

Engncd and gcaled this eleventh Of N0vember1975 [SEAL] Arrest.

RUTH. C. MSON C. MA'RSHALL DANN o-llu'slmg ()fjicer ('ummissimu'r u]Parents um! Trudwnurks

1. A vehicle comprising a frame, an engine mounted on said frame andincluding a crankshaft, a gear case mounted on said frame, a pair ofhydrostatic transmissions respectively detachably mounted on the opposedsides of the exterior of said gear case and each including an inputshaft extending into said gear case, an output shaft extending into saidgear case in parallel relation to said input shaft, a pivotally mountedswash plate to provide for swash plate movement in response to controlarm movement whereby to locate said swash plate in positions affordingneutral, forward and reverse drive conditions of said transmissions,power input means connected to said crankshaft exteriorly of said gearcase and connected to said hydrostatic transmission input shaftsinteriorly of said gear case, power output means connected interiorly ofsaid gear case to said hydrostatic transmission output shafts andincluding a pair of axle shafts, first and second sprockets fixedrespectively on said axle shafts, first and second endless flexibletracks respectively trained about said first and second sprockets, andmeans for moving said control arms to provide for coordinated speed anddirection control of said tracks.
 2. A vehicle comprising a frame, anengine mounted on said frame and including a crankshaft, a gear casemounted on said frame, a pair of hydrostatic transmissions respectivelydetachably mounted on the opposed sides of the exterior of said gearcase and each including an input shaft extending into said gear case, anoutput shaft extending into said gear case in parallel relation to saidinput shaft, a pivotally mounted swash plate, and a control armconnected to said swash plate to provide for swash plate movement inresponse to control arm movement whereby to locate said control arm andswash plate in positions affording neutral, forward and reverse driveconditions of said transmissions, power input means connected to saidcrankshaft exteriorly of said gear case and connected to saidhydrostatic transmission input shafts interiorly of said gear case,power output means connected interiorly of said gear case to saidhydrostatic transmission output shafts and including a pair of axleshafts, first and second sprockets fixed respectively on said axleshafts, first and second endless flexible tracks respectively trainedabout said first and second sprockets, a control member, means mountingsaid control member on said frame for movement about a first axis, meansmounting said control member on said frame for movement about a secondaxis at right angles to said first axis, a pair of links connectedrespectively to said control arms and to said control member at the samedistance from and on opposite sides of said first axis and at the samedistance from and on the same side of said second axis, a stop includinga blocking portion, means mounting said stop on said frame for movementof said blocking portion relative to a position in the path of controlmember movement about one of said axes to limit control member movementabout said one axis to thereby prevent movement of said control arm toreverse drive positions, and a spring connected to said stop for biasingsaid blocking portion to said position.
 3. A vehicle comprising a frame,an engine mounted on said frame and including a crankshaft, a gear casemounted on said frame, a pair of hydrostatic transmissions respectivelydetachably mounted on the opposed sides of the exterior of said gearcase and each including an input shaft extending into said gear case, anoutput shaft extending into said gear case in parallel relation to saidinput shaft, a pivotally mounted swash plate, a control arm conneCted tosaid swash plate to provide for swash plate movement in response tocontrol arm movement whereby to locate said swash plate in positionsaffording neutral, forward and reverse drive conditions of saidtransmissions, and hydraulic fluid passages, power input means connectedto said crankshaft exteriorly of said gear case and connected to saidhydrostatic transmission input shafts interiorly of said gear case,power output means connected interiorly of said gear case to saidhydrostatic transmission output shafts and including a pair of axleshafts, a hydraulic fluid radiator mounted on said frame and includinghydraulic fluid passages, a hydraulic fluid circulation system includinghydraulic connections coupling said transmission passages, said radiatorpassages and said gear case in a closed series hydraulic circuit, firstand second sprockets fixed respectively on said axle shafts, first andsecond endless flexible tracks respectively trained about said first andsecond sprockets, and means for moving said control arms to provide forcoordinated speed and direction control of said tracks.
 4. A vehiclecomprising a gear case, an engine connected to said gear case andincluding a crankshaft, a pair of transmissions respectively detachablymounted on the opposed sides of the exterior of said gear case and eachincluding an input shaft extending into said gear case, an output shaftextending into said gear case in parallel relation to said input shaft,and a control arm operable to provide neutral, forward and reverse driveconditions, power input means connected to said crankshaft exteriorly ofsaid gear case and connected to said transmission input shaftsinteriorly of said gear case, and power output means connectedinteriorly of said gear case to said transmission output shafts andincluding a pair of co-axial power output shafts extending exteriorly ofsaid gear case.
 5. A vehicle in accordance with claim 4 and including aframe and wherein said gear case and said engine are mounted on saidframe, wherein said pair of transmissions comprise hydrostatictransmissions each also including a pivotally mounted swash plate, andwherein said control arm is connected to said swash plate to provide forswash plate movement in response to control arm movement whereby tolocate said swash plates in positions affording neutral, forward andreverse drive conditions, and further including first and secondsprockets fixed respectively on said power output shafts, first andsecond endless flexible tracks respectively trained about said first andsecond sprockets, and means for moving said control arms to provide forcoordinated speed and direction control of said tracks.
 6. A vehiclecomprising a frame, an engine mounted on said frame and including acrankshaft, a gear box mounted on said frame, a pair of hydrostatictransmissions respectively detachably mounted on the opposed sides ofthe exterior of said gear box and each including an input shaftextending into said gear box, an output shaft extending into said gearbox in parallel relation to said input shaft, a control arm operable toprovide neutral, forward and reverse drive conditions, and hydraulicfluid passages, a power input means connected to said crankshaftexteriorly of said gear box and connected to said hydrostatictransmission input shafts interiorly of said gear box, power outputmeans connected interiorly of said gear box to said hydrostatictransmission output shafts and including power output shafts extendingexteriorly of said gear box, a hydraulic fluid radiator mounted on saidframe and including hydraulic fluid passages, and a hydraulic fluidcirculation system including hydraulic connections coupling saidtransmission passages, said radiator passages and said gear box in aclosed series hydraulic circuit.
 7. A vehicle comprising a bodyincluding a bottom wall, a front wall extending from said bottom wall,opposed side walls extending from said bottom wall and from said frontwall, a powEr assembly including a frame connected to said body andincluding a dashboard, an engine mounted on said frame below saiddashboard and including an air fan arranged to direct air over saidengine from the rear thereof toward the front thereof, a gear boxmounted on said frame, a pair of hydrostatic transmissions detachablymounted on the exterior of said gear box and each including hydraulicpassages, an input shaft extending into said gear box, an output shaftextending into said gear box in parallel relation to said input shaft,and a control arm operable to provide neutral, forward and reverse driveconditions of said transmissions, power input means extending exteriorlyof said gear box and connected to said transmission input shaftsinteriorly of said gear box, power output means connected interiorly ofsaid gear box to said transmission output shafts and including poweroutput shafts extending exteriorly of said gear box, a hydraulic fluidradiator mounted on said frame and including hydraulic fluid passages, ahydraulic circulation system including hydraulic connections couplingsaid transmission passages, said radiator passages and said gear box ina closed series hydraulic circuit, a hood detachably connected to saidbody and comprising a front section including side walls and a top walland extending forwardly of said dashboard above said power assembly andto adjacent to said body front and side walls, and a rear sectionextending vertically from said dashboard to said bottom wall and betweensaid side walls, a first baffle supported by said body and locatedbetween said engine and said gear box and extending generally verticallyfrom said bottom wall to said front hood section and between said bodyside walls to define a forward compartment, and a rear compartmentcontaining said engine and closed at the rear by said rear hood section,said first baffle including an opening therein, a second bafflesupported by said body and extending generally horizontally across saidforward compartment from said radiator to said first baffle and toadjacent said body front and side walls to divide said forwardcompartment into a lower compartment containing said gear box and anupper air intake compartment, a front air inlet located in one of saidfront hood section side walls and communicating with said air intakecompartment, an air vent located in one of said front hood section sidewalls and communicating with said compartment containing said engine, arear air inlet located in said front hood section top wall, baffle meanssupported by said frame and extending rearwardly of said rear air inletfor conducting air from said rear air inlet rearwardly and above saidengine and underneath said dashboard for communication with the rear ofsaid compartment containing said engine, whereby air entering said rearair inlet is supplied to the rear of said compartment containing saidengine and is directed forwardly over said engine by said engine fan anddischarged through said air vent, coupling means connecting said enginecrankshaft and said power input means exteriorly of said gear box andextending through said opening, and a fan carried by said coupling meansadjacent to and concentrically with said opening, whereby air is drawninwardly of said front air inlet, through said intake compartment,through said radiator, through said compartment containing said gearbox, and through said opening into said compartment containing saidengine for discharge through said air vent.